scholarly journals Anterior Segment Biometry with Phenylephrine and Tropicamide during Accommodation Imaged with Ultralong Scan Depth Optical Coherence Tomography

2019 ◽  
Vol 2019 ◽  
pp. 1-5
Author(s):  
Junna Zhang ◽  
Yang Ni ◽  
Peng Li ◽  
Wen Sun ◽  
Mengyun Liu ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Corneal Thickness ◽  
Anterior Segment ◽  
Anterior Chamber Depth ◽  
Crystalline Lens ◽  
Repeated Measurements ◽  
Optical Coherence ◽  
Posterior Surface ◽  
Optical Zone

Purpose. To investigate the influence of phenylephrine and tropicamide on anterior segment biometry with ultralong scan depth optical coherence tomography (UL-OCT) during accommodation. Methods. In this study, 20 left eyes of healthy volunteers with a mean ± standard deviation age of 31.05 ± 5.84 years and a mean refraction of −1.16 ± 1.11 diopters (range 0∼−3.0 D) were imaged using UL-OCT after instillation of artificial tears, phenylephrine, and tropicamide in three follow-up trials, respectively. At each follow-up trial, two repeated measurements were performed at states of relax and 5D accommodative stimulation. The dimensional parameters included central corneal thickness (CCT), anterior chamber depth (ACD), pupil diameter (PD), lens thickness (LT), and horizontal radii of the lens anterior and posterior surface curvatures (LAC and LPC). Results. Tropicamide led to larger pupil, deeper ACD, thinner LT, and flatter crystalline lens surface (P<0.05). Phenylephrine induced an increase in PD (P<0.05), while no significant changes were seen in ACD, LT, LAC, and LPC (P>0.05). CCT did not change after both phenylephrine and tropicamide instillation in this study (P>0.05). Tropicamide induced the loss of accommodation and phenylephrine achieved pupil dilation without affecting the accommodation. PD, ACD decreased, LT increased significantly and the anterior and posterior surface of the lens in a 6.294 mm of diameter optical zone became steeper during accommodation after administration of phenylephrine (P<0.05). Conclusion. The anterior segment physiology changed after tropicamide instillation. Besides, tropicamide induced the loss of accommodation and phenylephrine preserved the accommodation with a larger pupil. And, the anterior and posterior surface of lens in a 6.294 mm of diameter optical zone became steeper during the accommodation.

scholarly journals Risk factors and evaluation of keratoconus progression after penetrating keratoplasty with anterior segment optical coherence tomography

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Junko Yoshida ◽  
Tetsuya Toyono ◽  
Rika Shirakawa ◽  
Takashi Miyai ◽  
Tomohiko Usui
Keyword(s):  
Risk Factors ◽  
Optical Coherence Tomography ◽  
Penetrating Keratoplasty ◽  
Corneal Thickness ◽  
Anterior Segment ◽  
Anterior Chamber Depth ◽  
Optical Coherence ◽  
Graft Size ◽  
Corneal Power ◽  
Corneal Thinning

Abstract To determine the risk factors and unique characteristics of keratoconus (KC) progression after penetrating keratoplasty (PK), anterior segment optical coherence tomography parameters were statistically analyzed in comparison with eyes undergoing PK for other diseases as a control. Ninety-one eyes maintaining clear PK grafts for over 10 years were divided into 2 groups according to the primary indication for PK (KC vs Others groups). Corneal thinning indicators (inferior host thinnest corneal thickness/central corneal thickness [IHT/CCT], inferior graft thinnest corneal thickness/CCT [IGT/CCT]), were smaller whereas anterior chamber depth, and steepest corneal power (Ks), and maximum corneal power (Kmax) were larger in the KC group with statistical significance. Graft size, Kmax and Ks correlated with IHT/CCT and IGT/CCT in the KC group. These correlations were not detected in controls. Graft size and postoperative period were selected by multivariate regression analysis as factors for corneal ectatic changes in the KC group. In conclusion, KC eyes long after PK show inferior graft and host corneal thinning, and corneal protrusion. Corneal power parameters such as Kmax or Ks can be used to monitor KC progression after PK. A small graft might lead to KC progression after PK.

Quantification of Trabecular-Iris Contact and its Prevalence by Optical Coherence Tomography in a Healthy Caucasian Population

2016 ◽  
Vol 27 (4) ◽  
pp. 417-422 ◽  
Author(s):  
José Ignacio Fernández-Vigo ◽  
Lucía De-Pablo-Gómez-De-Liaño ◽  
Cristina Fernández-Vigo ◽  
Inés Sánchez-Guillén ◽  
Enrique Santos-Bueso ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Anterior Chamber ◽  
Refractive Error ◽  
Axial Length ◽  
Corneal Thickness ◽  
Anterior Segment ◽  
Anterior Chamber Depth ◽  
Fourier Domain ◽  
Optical Coherence ◽  
Cross Sectional

Purpose To determine the prevalence of trabecular-iris contact (TIC) and quantify this contact in healthy Caucasian individuals using Fourier-domain optical coherence tomography (FD-OCT). Methods For this cross-sectional study, 2,012 eyes of 1,006 healthy subjects were recruited among individuals undergoing a routine ophthalmologic checkup. In each participant, age, sex, intraocular pressure, and spherical refractive error were first recorded along with anterior chamber depth and volume, central corneal thickness measured with the Pentacam, and axial length with the IOLMaster. Anterior chamber angle variables and the presence of TIC in the horizontal quadrants were determined by anterior segment FD-OCT (RTVue 100®). When TIC was observed, TIC length (TICL) and its percentage in relation to the length of the trabecular meshwork (TICL percentage) were also measured. Results Trabecular-iris contact in the horizontal quadrants was observed in 34 eyes of 25 patients, representing 1.6% of the total number of eyes examined. In this subgroup of individuals, mean age was 55.8 years, 84% were women, and spherical refractive error ranged from -0.25 to 8.25 D. Eyes with TIC showed an angle width of less than 23.2 degrees and axial length shorter than 23.7 mm. Mean TICL was 239 ± 79 μm (103-495 μm) and mean TICL percentage was 46.9% ± 13.9% (17.2%-76.3%). Conclusions The prevalence of TIC was low in this population. Fourier-domain optical coherence tomography emerged as useful to assess its prevalence and quantify the extent of TIC.

scholarly journals Assessment of Full-Eye Response to Osmotic Stress in Mouse Model In Vivo Using Optical Coherence Tomography

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Yang Ni ◽  
Baisheng Xu ◽  
Lan Wu ◽  
Chixin Du ◽  
Bo Jiang ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Osmotic Stress ◽  
Corneal Thickness ◽  
Anterior Chamber Depth ◽  
Crystalline Lens ◽  
Angle Closure ◽  
Optical Coherence ◽  
Ocular Disorders ◽  
Almost All

NaCl based solutions were applied as osmotic stress agents to alter the hydration state of the mouse eye. Full-eye responses to these osmotic challenges were monitored in vivo using a custom-built optical coherence tomography (OCT) with an extended imaging range of 12.38 mm. Dynamic changes in the mouse eye were quantified based on the OCT images using several parameters, including the central corneal thickness (CCT), the anterior chamber depth (ACD), the crystalline lens thickness (LT), the cornea-retina distance (CRD), the iris curvature (IC), and the lens scattering intensity (LSI). Apparent but reversible changes in the morphology of almost all the ocular components and the light transparency of the lens are exhibited. Particularly, the ocular dehydration induced by the hypertonic challenges resulted in a closing of the iridocorneal angle and an opacification of the lens. Our results indicated that the ocular hydration is an important physiological process which might be correlated with various ocular disorders, such as dry eye, cataract, and angle-closure glaucoma, and would affect the biometry and imaging of the eye. OCT uniquely enables the comprehensive study of the dynamic full-eye responses to the ocular hydration in vivo.

scholarly journals Optical Coherence Tomography Reveals Sigmoidal Crystalline Lens Changes during Accommodation

Vision ◽  
2018 ◽  
Vol 2 (3) ◽  
pp. 33
Author(s):  
George Gibson ◽  
Fiona Cruickshank ◽  
James Wolffsohn ◽  
Leon Davies
Keyword(s):  
Optical Coherence Tomography ◽  
Refractive Index ◽  
Contact Lenses ◽  
Anterior Segment ◽  
Anterior Chamber Depth ◽  
Crystalline Lens ◽  
Optical Coherence ◽  
Accommodative Response ◽  
Schematic Eye ◽  
Lens Surface

This study aimed to quantify biometric modifications of the anterior segment (AS) during accommodation and to compare them against changes in both accommodative demand and response. Thirty adults, aged 18–25 years were rendered functionally emmetropic with contact lenses. AS optical coherence tomography (AS-OCT) images were captured along the 180° meridian (Visante, Zeiss Meditec, Jena, Germany) under stimulated accommodative demands (0–4 D). Images were analysed and lens thickness (LT) was measured, applying a refractive index correction of 1.00. Accommodative responses were also measured sequentially through a Badal optical system fitted to an autorefractor (Shin Nippon NVision-K 5001, Rexxam, Japan). Data were compared with Dubbelman schematic eye calculations. Significant changes occurred in LT, anterior chamber depth (ACD), lens centroid (i.e., ACD + LT/2), and AS length (ASL = ACD + LT) with accommodation (all p < 0.01). There was no significant change in CT with accommodation (p = 0.81). Measured CT, ACD, and lens centroid values were similar to Dubbelman modelled parameters, however AS-OCT overestimated LT and ASL. As expected, the accommodative response was less than the demand. Interestingly, up until approximately 1.5 D of response (2.0 D demand), the anterior crystalline lens surface appears to be the primary correlate. Beyond this point, the posterior lens surface moves posteriorly resulting in an over-all sigmoidal trajectory. he posterior crystalline lens surface demonstrates a sigmoidal response with increasing accommodative effort.

scholarly journals Role of anterior segment optical coherence tomography in the evaluation of microbial keratitis

2021 ◽  
Vol 7 (3) ◽  
pp. 548-553
Author(s):  
Isha Chaturvedi ◽  
Kamaljeet Singh ◽  
Jagriti Rana ◽  
Kshama Dwivedi ◽  
Reena Sachan
Keyword(s):  
Optical Coherence Tomography ◽  
Corneal Thickness ◽  
Anterior Segment ◽  
Morphological Characteristics ◽  
Objective Evaluation ◽  
Response To Treatment ◽  
Optical Coherence ◽  
Microbial Keratitis ◽  
The Mean

Anterior segment optical coherence tomography (AS-OCT) is a newer technology that provides two-dimensional images of corneal infiltration. This study was undertaken to assess whether AS-OCT can aid objective evaluation and response to treatment in resolving microbial keratitis. This prospective study was performed on 17 patients of who underwent slit lamp and AS-OCT examination at presentation and follow up on days 3, 7, 14, 28 and 6 weeks. A standardized scanning protocol was used to measure the corneal thickness (CT) and infiltrate thickness (IT) using the caliper tool of a commercially available AS-OCT device. The mean CT in the infiltrated area and mean IT, both were thickest at presentation (710.88 um and 288.76 um respectively). The mean CT decreased to 665.12 µm, 650.24 µm, 584.35 µm, 549 µm, 507.47 µm on days 3, 7, 14, 28 and 6 weeks respectively. Similarly, the mean IT decreased to 287.24 µm, 244.41 µm, 197 µm, 174.59 µm and 154.82 µm. Paired t- test was used to calculate the statistical change in CT and IT, which was significant (p&#60;0.0001) at 6 weeks, at the rate of 0.67% and 1.01% per day. AS-OCT can show morphological characteristics of microbial keratitis and give quantitative assessment at every follow up.

scholarly journals Assessment of Anterior Chamber by Ultrasound Biomicroscopy and Anterior Segment Optical Coherence Tomography in Patients with Inflammatory Glaucoma

2019 ◽  
Vol 47 (12) ◽  
pp. 5950-5956 ◽  
Author(s):  
Yiyong Qian ◽  
Lin Liu ◽  
Yuehui Shi ◽  
Minli Wang ◽  
Min Li ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Anterior Chamber ◽  
Ciliary Body ◽  
Imaging Techniques ◽  
Corneal Thickness ◽  
Anterior Segment ◽  
Anterior Chamber Depth ◽  
Ultrasound Biomicroscopy ◽  
Optical Coherence ◽  
Pars Plana

Objective To investigate the clinical indications of ultrasound biomicroscopy (UBM) and anterior segment optical coherence tomography (AS-OCT) in eyes with inflammatory glaucoma. Methods Sixteen patients (16 eyes) with inflammatory glaucoma were analysed retrospectively. All of the subjects underwent UBM and AS-OCT scans, measuring the following parameters: central corneal thickness (CCT), central anterior chamber depth (ACD), angle-opening distance (AOD500), and trabecular-iris angle (TIA500) in four quadrants. Results Both the UBM and AS-OCT generated detailed, high-resolution images of the anterior segments of the eyes with inflammatory glaucoma. Moreover, the UBM and AS-OCT exhibited statistically similar measurement results for all of the indices. A Bland–Altman analysis showed a high level of agreement between the two imaging techniques. Additionally, the UBM was able to visualize the ciliary body and pars plana, while the cells and the flare in the anterior chamber appeared more pronounced in the UBM images. Conclusions Both the UBM and AS-OCT are useful tools for anterior segment imaging and taking measurements needed for evaluating inflammatory glaucoma. The AS-OCT has the advantages of being noninvasive and fast, whereas the UBM is presently unparalleled in the visualization of the ciliary body and pars plana.

scholarly journals Agreement between anterior segment Optical Coherence Tomography, Lenstar and Ultrasound Biomicroscopy measurements of anterior segment parameters

2019 ◽  
Author(s):  
Ziyan Yu ◽  
Ting Huang ◽  
Qiao Yu ◽  
Jun Kong ◽  
Bo Qu
Keyword(s):  
Optical Coherence Tomography ◽  
Anterior Chamber ◽  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Anterior Segment ◽  
Anterior Chamber Depth ◽  
Ultrasound Biomicroscopy ◽  
Optical Coherence ◽  
Significant Difference ◽  
Medical University

Abstract Purpose To compare anterior chamber depth (ACD) and central corneal thickness (CCT) measurements by anterior segment optical coherence tomography (AS-OCT), Lenstar and ultrasound biomicroscopy (UBM). Methods A retrospective cross section study. A total of 83 eyes from 54 patients were included. Central corneal thickness (CCT) and anterior chamber depth (ACD) values obtained from three devices (AS-OCT, Lenstar and UBM) were recorded. All patients were collected from Oct. 2015 to Aug. 2016 in the Fourth Affiliated Hospital of China Medical University. Differences of these three devices (ACD and CCT) were statistically analyzed by randomized blocks analysis. Pearson correlative analysis and Bland-Altman analysis were used to compare the correlation and agreement. Results There’s no significant difference in measuring ACD by Lenstar and UBM (P>0.05), but there were significant differences in other two groups (AS-OCT and UBM, AS-OCT and Lenstar) (P<0.05). There were significant differences in the mean CCT measured by the three devices (P<0.05). There were high correlation in measuring ACD (all P<0.001, r1=0.928,r2=0.982,r3=0.932, respectively), and CCT(all P<0.001,r1=0.957,r2=0.949,r3=0.928, respectively). Conclusion AS-OCT, Lenstar and UBM yielded comparable results and are all can be used interchangeably for anterior segment measurements.

scholarly journals Comparison of a new anterior segment optical coherence tomography and Oculus Pentacam for measurement of anterior chamber depth and corneal thickness

2020 ◽  
Vol 8 (14) ◽  
pp. 857-857
Author(s):  
Xuepei Li ◽  
Yijing Zhou ◽  
Charlotte Aimee Young ◽  
Aiming Chen ◽  
Guangming Jin ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Anterior Chamber ◽  
Corneal Thickness ◽  
Anterior Segment ◽  
Anterior Chamber Depth ◽  
Optical Coherence

Utility of the Anterior Segment Optical Coherence Tomography for Measurements of Central Corneal Thickness

2007 ◽  
Vol 48 (12) ◽  
pp. 1643 ◽  
Author(s):  
Hyoung Sub Shim ◽  
Chul Young Choi ◽  
Hee Gyung Lee ◽  
Myoung Joon Kim ◽  
Hung Won Tchah
Keyword(s):  
Optical Coherence Tomography ◽  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Anterior Segment ◽  
Optical Coherence

scholarly journals The Use of Anterior-Segment Optical-Coherence Tomography for the Assessment of the Iridocorneal Angle and Its Alterations: Update and Current Evidence

2021 ◽  
Vol 10 (2) ◽  
pp. 231
Author(s):  
Giacinto Triolo ◽  
Piero Barboni ◽  
Giacomo Savini ◽  
Francesco De Gaetano ◽  
Gaspare Monaco ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Intraocular Pressure ◽  
Clinical Relevance ◽  
Anterior Segment ◽  
Angle Closure ◽  
Current Evidence ◽  
Optical Coherence ◽  
Iridocorneal Angle ◽  
Wide Range

The introduction of anterior-segment optical-coherence tomography (AS-OCT) has led to improved assessments of the anatomy of the iridocorneal-angle and diagnoses of several mechanisms of angle closure which often result in raised intraocular pressure (IOP). Continuous advancements in AS-OCT technology and software, along with an extensive research in the field, have resulted in a wide range of possible parameters that may be used to diagnose and follow up on patients with this spectrum of diseases. However, the clinical relevance of such variables needs to be explored thoroughly. The aim of the present review is to summarize the current evidence supporting the use of AS-OCT for the diagnosis and follow-up of several iridocorneal-angle and anterior-chamber alterations, focusing on the advantages and downsides of this technology.

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